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Building Information Systems Chapter 12B Building Information Systems

Systems Development Life Cycle Organized way to build information systems Consists of five phases Entire usable life of the system

SDLC

Systems Development Life Cycle Phase 1: needs analysis Users identify a need Solves three main problems Define the problem Present possible solutions Determine the best solution Technology analysts talk with users Define the problem using a description tool A solution is presented to a manager Teaching tip Structured English is covered in chapter 13. The term used is pseudo code.

Systems Development Life Cycle Phase 2: Systems design Solution is defined Data storage User interface Reports Several design tools Top down design Bottom up design CASE tools used to build prototypes Computer aided software engineering

Systems Development Life Cycle Phase 3: Development Solution to the problem is built Programmers play a key role Solutions may be purchased Solutions may be built locally Technical writers create instructions Solution is repeatedly tested Teaching tip Companies understand the SDLC and attempt to work with clients to provide the program they need. Oracle for instance has several add-ons for its core DBMS lines. Oracle financials, for instance, allows companies to completely track and maintain it’s cash flow and costs.

Systems Development Life Cycle Phase 4: Implementation Installation of hardware and software Users must convert to the solution Direct conversion Parallel conversion Phased conversion Pilot conversion Trainers and support personnel are critical Teaching tip Pilot programs are often referred to as beta testing. The beta testers work with the product to guarantee that it is ready for release.

SDLC Conversion

Systems Development Life Cycle Phase 5: Maintenance IT professionals continue to monitor Bugs are fixed New features are added Users often suggest bugs or features Teaching tip Microsoft continues to maintain their products, sometimes years after launch. Windows XP recently received its second service pack while Windows 2000 is on it’s fourth.

Evolving System Design Methods Problems with SDLC SDLC is an old process Very slow process Companies need to respond quickly

Evolving System Design Methods Rapid Application Design (RAD) Develops IS systems quickly Several products exist Slightly different development phases Teaching tip Microsoft Visual Basic is one tool often associated with RAD.

RAD SDLC

Evolving System Design Methods RAD Phase 1: Requirements planning Requirements for project are defined Joint requirements planning (JRP) Involves programmers and managers Managers from affected departments provide guidance

Evolving System Design Methods RAD Phase 2: User design Joint application design (JAD) System analysts and users User provides the details System analyst solve the technical details Discussion point Have the students discuss the usefulness of user input in the design phase. Discuss both pros and cons.

Evolving System Design Methods RAD Phase 3: Rapid construction IS professionals develop the project A variety of tools can be used Users approve each portion

Evolving System Design Methods RAD Phase 4: Transition System is tested on sample data Users are trained on the sample New system runs parallel to existing Phase complete when bugs are gone Old system removed

Evolving System Design Methods RAD Phase 5: Maintenance Traditionally not part of RAD All systems need periodic maintenance

Evolving System Design Methods Object Oriented Systems Analysis OOSA Project elements are defined using objects Objects are self contained programming constructs Objects have data and functionality Objects are linked together Java and C++ are typical tools

Chapter 12B End of Chapter